Sex charge added in Colo. school girl killing case

This photo provided by the Jefferson County Sheriff's Office shows Austin Reed Sigg on Nov. 27, 2012. Sigg, 18, accused of kidnapping and killing a 10-year-old Westminster girl, is due in court for a hearing laying out the evidence against him. Sigg's hearing on Friday comes a day after the Colorado Supreme Court overturned a judge's decision to keep proceedings closed to the public.(AP Photo/Jefferson County Sheriff's Office)

This photo provided by the Jefferson County Sheriff's Office shows Austin Reed Sigg on Nov. 27, 2012. Sigg, 18, accused of kidnapping and killing a 10-year-old Westminster girl, is due in court for a hearing laying out the evidence against him. Sigg's hearing on Friday comes a day after the Colorado Supreme Court overturned a judge's decision to keep proceedings closed to the public.(AP Photo/Jefferson County Sheriff's Office)

GOLDEN, Colo. (AP) — Colorado prosecutors have added a sexual exploitation charge against an 18-year-old accused of kidnapping and killing a suburban Denver school girl.

Austin Sigg's preliminary hearing is scheduled for Friday in Golden.

He's also charged with murder, kidnapping, sexual assault and robbery in the October killing of 10-year-old Jessica Ridgeway of Westminster, and accused of attacking a runner.

The Colorado Supreme Court overturned a judge's decision to close Friday's proceedings in which prosecutors plan to lay out their case.

Prosecutors expect the hearing to move ahead, even though a hearing earlier this month was canceled as the media challenged the decision to close it.

Attorneys for the state say they're dropping two charges against Sigg but adding the exploitation charge because of a video of a child found during their investigation.